Patent GB-605182-A (GB)
Title: Improvements in or relating to fastenings or methods of forming the same
IPC: F16B19/10
Filed: 1945-12-18
Abstract: 605,182. Eyelets. BRITISH UNITED SHOE MACHINERY CO., Ltd. Dec. 18, 1945, No. 34208. Convention date, Dec. 20, 1944. [Class 43] [Also in Group V] A flanged one-piece fastening, e.g. an eyelet, rivet or grommet, with or without anti-twist projections, is of thermoplastic resinous material, unplasticized or substantially so, which is cold-worked, giving it greater strength, and dispensing with applying and protecting a finish. A strong resilient fastening is formed from a tubular blank of the material, which can be mechanically shaped without extraneous heating, part at least of the blank being confined against lateral outward movement, and while at room temperature being subjected to a momentary endwise impact. A rigid tubular blank 10 of thermoplastic resinous material is placed in the upper end of a vertical sleeve 12 having a ridge 14 round the inner edge of its top surface, and is supported by a rod 16 housed in the sleeve. A die 18, having a cylindrical, central projection 20 of greater diameter than the interior of the blank, descends vertically to engage the blank and effects, preferably by a single sharp impact, a flowing of the material about the ridge 14 and into a channel 22 formed round the pilot portion 20, thus forming the flange. If there is an excess of plastic material it is pinched off between the top of the sleeve 12 and a lip 24 at the edge of the channel 22. To remove the eyelet either the rod 16 may be used, or a telescopic sleeve (not shown) on the die 18. To set the eyelet in two layers of material, 28, 30, e.g. on a shoe, it is inserted through a hole in the work and is set by a machine having a lower die in the form of a sleeve 32, which has in its top an annular recess to support the head of the eyelet, and which is stepped so that it has a smaller diameter at its upper part 34 than at its lower part 36. this step being engaged by a flange 39 of a spring-urged plunger 38, which has an enlarged upper end 41 with its upper surface slightly rounded to permit smooth entry into the barrel of the eyelet. Coaxial with the die 32 is an upper die 42 having a central, slightly tapering pilot portion 44 with a rounded lower surface and with a recess 46 round its root to accommodate the end of the eyelet when upset. The upsetting operation is as before, and causes the edges of the flanges to sink slightly into the material 28, 30. The eyelet may have an addditional cold working operation performed on it, e.g. if it is initially made with a tapering barrel it may be cold worked laterally to change or straighten the taper, or to decrease the wall thickness and increase the length. An eyelet may be made initially by compression moulding and then cold worked to increase its strength. Anti-twist projections, conveniently in the form of small ribs lying across the angle between the head flange and the outside of the barrel of the eyelet, may be provided by making cuts in the annular ridge 14 of the sleeve 12. Materials suggested are the copolymer of vinyl chloride and vinyl acetate, polyamides, polyvinyl chloride, vinyl chloride copolymers, vinylidene chloride copolymers, polymethyl methacrylate, cellulose acetate, cellulose acetate butycate and ethyl cellulose.